In Kanpur, India's and the world's most polluted city, PM2.5 (particulate matter like small particles of soot, dust etc) present in the air is about five times higher than the WHO's most lenient guideline value.
Faridabad and Varanasi are not far behind in WHO's recent database containing a list of pollution levels in over 1,000 cities worldwide. A WHO press release noted that 97% of the cities in low and middle income countries with over 1 lakh inhabitants do not meet WHO air quality guidelines.
Of the 20 most polluted cities, 14 are in India , while two cities — Peshawar and Rawalpindi — are in Pakistan. Here's a look at the highest PM 2.5 levels worldwide:
Note: In chart, I: India, C: Cameroon, P: Pakistan, U: Uganda, B: Bangladesh, Q: Qatar
Most of the polluting cities in India are concentrated in the Northern region. Here's a map showing the most polluted cities in India:
